U.S. patent number 5,072,444 [Application Number 07/425,889] was granted by the patent office on 1991-12-10 for central controller with adaptive message handling characteristics.
This patent grant is currently assigned to Motorola, Inc.. Invention is credited to Robert L. Breeden, Prabbakar Muppidi.
United States Patent |
5,072,444 |
Breeden , et al. |
December 10, 1991 |
Central controller with adaptive message handling
characteristics
Abstract
A central controller operating as a pager terminal for
receiving, handling, and transmitting messages is shown that
adaptively alters its message handling characteristics in order to
improve the overall throughput of the central controller. The
channel loading characteristics, based upon the time of day, are
used in order to vary the limitation of the size of message
received by the central controller as well as vary the transmission
size and age of messages prior to transmission. Additionally,
channel loading may be determined by determining the total size of
messages within the central controller. In response to the total
size determination, the limitation of the message size received by
the controller may be varied. Furthermore, the transmission size
and age of messages prior to transmission may be varied in response
to the total size determination. The central controller may also
adopt these operations in response to the combination of the total
size determination and channel loading based upon the time of day
characteristics.
Inventors: |
Breeden; Robert L. (Boynton
Beach, FL), Muppidi; Prabbakar (Boynton Beach, FL) |
Assignee: |
Motorola, Inc. (Schaumburg,
IL)
|
Family
ID: |
23688462 |
Appl.
No.: |
07/425,889 |
Filed: |
October 23, 1989 |
Current U.S.
Class: |
370/235; 370/313;
340/7.3 |
Current CPC
Class: |
H04W
88/185 (20130101) |
Current International
Class: |
H04Q
7/10 (20060101); H04Q 7/06 (20060101); H04J
003/24 (); G08B 005/22 () |
Field of
Search: |
;370/82,84,85.7,94.1,95.1,110.1 ;379/59,63,56,57
;340/825.44,825.47,825.48 ;455/33,34,53,54,56 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Olms; Douglas W.
Assistant Examiner: Chin; Wellington
Attorney, Agent or Firm: Koch; William E. Ingrassia; Vincent
B. Sarli, Jr.; Anthony J.
Claims
What is claimed is:
1. A central controller for receiving, handling and transmitting
messages comprising:
means for receiving an incoming message, the incoming message
having a size based upon the amount of time elasped during the
reception of the incoming message;
controlling means for producing a control signal in order to
optimize the transmission of the plurality of messages;
limiting means coupled to the receiving means nd responsive to the
control signal for limiting the size of the incoming message to a
maximum size in response to the control signal, thereby producing a
limited message, wherein the maximum size is varied;
transmitting means for transmuting the limited message to a
plurality of selective call receivers,
thereby varying the maximum size of messages transmitted to the
selective call receivers in order to optimize the transmission of
the plurality of messages.
2. A central controller for receiving, handling and transmitting
messages comprising:
means for receiving an incoming message, the incoming message
having a size based upon the amount of time necessary to transmit
the incoming message;
controlling means for producing a control signal in order to
optimize the transmission of the plurality of messages;
limiting means coupled to the receiving means and responsive to the
control signal for limiting the size of the incoming message to a
maximum size in response to the control signal thereby producing a
limited message, wherein the maximum size is varied;
transmitting means for transmitting the limited message to a
plurality of selective call receivers,
thereby varying the maximum size of messages transmitted to the
selective call receivers in order to optimize the transmission of
the plurality of messages.
3. A central controller for receiving, handling and transmitting
messages comprising:
means for receiving an incoming message, the incoming message
having a size, the receiving means having a memory means for
holding the incoming message and the size of the incoming message
is based upon the amount of memory occupied by the incoming
message;
controlling means for producing a control signal in order to
optimize the transmission of the plurality of messages;
limiting means coupled to the receiving means and responsive to the
control signal for limiting the size of the incoming message to a
maximum size in response to the control signal, thereby producing a
limited message, wherein the maximum size is varied;
transmitting means for transmitting limited message to a plurality
of selective call receivers,
thereby varying the maximum size of messages transmitted to the
selective caller receivers in order to optimize the transmission of
the plurality of messages.
4. A central controller for receiving, handling and transmitting
messages comprising:
means for receiving an incoming message, the incoming message
having a size;
controlling means for producing a control signal in order to
optimize the transmission of the plurality of messages;
limiting means coupled to the receiving means and responsive to he
control signal for limiting the size of the incoming message to a
maximum size in response the control signal, hereby producing a
limited message, wherein the maximum size is varied, wherein
limiting the size of the incoming message includes truncating the
incoming messages;
transmitting means for transmitting the limited message to a
plurality of selective call receivers,
thereby varying the maximum size of messages transmitted to the
selective caller receivers in order to optimize the transmission of
the plurality of messages.
5. A central controller for receiving, handling and transmitting
messages comprising:
means for receiving an incoming message, the incoming message
having a size;
controlling means for producing a control signal in order to
optimize the transmission of the plurality of messages;
limiting mean coupled to the receiving means and responsive to the
control signal for limiting the size of the incoming message to a
maximum size in response to the e control signal, thereby producing
a limited message, wherein the maximum size is varied, wherein
limiting the size of the incoming message includes selectively
removing portions to the incoming message;
transmitting means for transmitting h the limited message to a
plurality of selective call receivers,
thereby varying the maximum size of messages transmitted to the
selective caller receivers in order to optimize the transmission of
the plurality of messages.
6. The central controller of claim 5 wherein the incoming message
is an audiomessage having silent portions and limiting the size of
the message includes removing the silent portions.
7. A central controller for receiving, handling and transmitting
messages comprising:
means for receiving an incoming message, the incoming message
having a size;
controlling means for producing a control signal in order to
optimize the transmission of the plurality of messages;
limiting means coupled to the e receiving means and responsive to
he control signal for limiting the size of the incoming message to
a maximum sie in response the controls signal, thereby producing a
limited message, wherein the maximum size is varied, wherein the
incoming message is received from a sending unit and the receiving
means communicates the maximum size of the incoming message to the
sending unit;
transmitting means for transmitting the limited message to a
plurality of selective caller receivers,
thereby varying the maximum size f messages transmitted to the
selective caller receivers index to optimize the transmission of to
the plurality of messages.
8. A central controller for receiving, handling and transmitting
messages comprising:
means for receiving an incoming message, the incoming message
having a size;
controlling means for producing a control signal in order to
optimize the transmission of the plurality of messages;
limiting means coupled oh e receiving and and responsive to he
control signal for limiting the size of the incoming message to a
maximum size in response to the control signal, thereby producing a
limited message, wherein the maximum size is varied;
transmitting means for transmitting limited message to a plurally
of selective caller receivers, wherein the incoming message is
intend for reception by a particular selective call receiver and
the control signal si capable of gearing one of a plurality of
maximum size signals, and each of the plurality of the selective
caller receivers has a corresponding maximum size signal, wherein
the control signal generates a maximum size corresponding to the
particular selective call receiver;
thereby varying the maximum size of messages transmitted to the
selective caller e receivers in order to optimize the transmission
the plurality of messages.
9. A central controller for receiving, handling and transmitting
messages comprising:
means for receiving an incoming message, the incoming message
having a size;
controlling means for producing a control signal in order to
optimize the transmissions the plurally of messages;
limiting means coupled oh e receiving means and responsive to the
control signal for limiting the size of the incoming message to a
maximum size in response to the control signal, thereby producing a
limited message, wherein the maximums size is varied;
transmitting means for transmitting the limited message to a
plurality of selective call receivers,
thereby varying the maximum size of messages transmitted to the
selective call receivers in order to optimize the transmission of
the plurality of messages;
a means to generating a time signal indicative to the time of day
and day of the week information, thereby varying maximum size of
the incoming messages as a function the time of day and the day of
the week; and wherein
the controlling means generates the control signal as a function to
the time signal, thereby varying the maximum size of the incoming
message as a function of day.
10. The central controller of claim 9 wherein the time signal
further includes date information, thereby varying the maximum size
the incoming signal as a function of the time of day and the
data.
11. A central controller for receiving, handling and transmitting
messages comprising:
means for receiving an incoming messages, the incoming message
having a size;
controlling means for producing a control signal in order to
optimize the transmission of the plurality of messages;
limiting means coupled to the e receiving means and responsive to
the control signal for limiting the size of the incoming message to
a maximum size in response to the control signal, thereby producing
a limited message, wherein the maximum size is varied;
transmitting means for transmitting the limited message to a
plurality of selective call receivers,
thereby varying the maximum size of messages transmitted to the
selective call receivers in order to optimize the transmission the
plurality of messages, wherein the transmitting means transits a
plurality of messages and the transmit means includes:
memory mean for holding the plurality of messages wherein the
plurality of messages have a total size;
means for generating a size signal indicative to f the total size
of the plurality of messages; and wherein
the controlling means generates the control signal as a function of
the size signal, thereby varying the maximum size of the incoming
message as a function of the total size of the plurality of
messages held within the storage means.
12. The central controller of claim 11 wherein the total size is
based upon the amount of memory occupied by the plurality of
messages.
13. The central controller of claim 11 wherein the total size is
based upon the transmission time of the plurality of messages.
14. The central controller of claim 11 further comprising:
a means for generating a time of day signal; and wherein
the controlling means generates the control signal as a function of
the size signal and the time of day signal, thereby varying the
size of the incoming messages as a function of the total size of
the plurality of messages held within the storage means and the
time of day.
15. A central controller for receiving, handling and transmitting
messages comprising:
receiving means for receiving a plurality of messages;
memory means coupled to the receiving means for accumulating the
plurality of messages, wherein the plurality of messages have a
total size;
measuring means coupled to the memory means for generating a total
size signal indicative of the total size of the plurality of
messages;
time keeping means for generating a time signal indicative of the
time of day.
controlling means responsive to the time signal for generating a
maximum size signal as a function of the time signal;
analyzing means responsive to the total size signal and the maximum
size signal for generating a transmit signal in response to the
total size signal being substantially equal to the maximum size
signal; and
transmitting means coupled to the memory means and responsive to
the transmit signal for transmitting the plurality of messages
within the memory means in response to the transmit signal,
thereby varying the size of the transmission of the plurality of
messages by the time of day.
16. The central controller of claim 15 wherein the total size of
the plurality of messages within the memory means is based upon the
time necessary to transmit the plurality of messages within the
memory means.
17. The central controller of claim 15 wherein the total size of
the plurality of messages within the memory means is based upon the
number of messages within the memory means.
18. The central controller of claim 15 wherein the total size of
the plurality of messages within the memory means is based upon the
amount of memory occupied by the plurality of messages.
19. The central controller of claim 15 wherein the plurality of
messages are transmitted in a batch protocol, wherein the plurality
of messages occupy a plurality of batches, each batch having a
predetermined number of slots, a slot having either address for
message information, and each message having an address portion and
a data portion and each message being transmitted within contiguous
slots, wherein the address portion of the message may only occur
within a predetermined slot within each batch, thereby providing
for the possibility of leaving several slots within the plurality
of batches vacant of either address or data information, wherein a
batch is considered full when the number of slots having address
for data information within the batch is greater than a threshold
signal and the measuring means determines the size of the plurality
of messages based upon the number of full batches.
20. The central controller of claim 18 wherein the controlling
means additionally generates the threshold signal as a function of
the time of day, and the measuring means being coupled to the
controlling means responds to the threshold signal for determining
when a batch is full batch, thereby varying the number of vacant
slots within a full batch by the time of day.
21. A central controller for receiving, handling, and transmitting
message comprising:
receiving means for receiving a plurality of messages;
memory means coupled to the receiving means for accumulating the
plurality of messages, wherein the plurality of messages have an
age indicative of the time elapsed while the messages are within
the memory means;
determining means coupled to the memory means for determining the
age of the messages within the memory means and for generating a
message age signal in response thereof;
time keeping means for generating a time signal indicative of the
time of day;
controlling means responsive to the time signal for generating a
maximum age signal as a function of the time signal;
analyzing means responsive to the message age signal and the
maximum age signal for generating a transmit signal in response to
the message age signal being substantially equal to the maximum age
signal; and
transmitting means coupled to the memory means and responsive to
the transmit signal for transmitting the plurality of messages
within the memory means in response to the transmit signal,
thereby varying the maximum age of the messages within the memory
means prior to transmission by the time of day.
22. The central controller of claim 21 wherein the messages within
the memory means have a total size and the central controller
further comprises:
measuring means coupled to the memory means for generating a total
size signal indicative of the total size of the plurality of
messages; and wherein
the controlling means additionally generates a maximum size signal
as a function of the time signal; and
the analyzing means being additionally responsive to the total size
signal, and the maximum size signal generates a transmit signal in
response to the total size signal being substantially equal to the
maximum size of the message age signal being substantially equal to
the maximum age signal,
thereby transmitting the messages within the memory means either
when the maximum size for maximum age is substantially realized,
and varying the maximum size and the maximum age as a function of
the time of day.
23. The central controller of claim 21 wherein the age of the
message within the memory represents the age of the oldest message
within the memory means, and the age signal generated by the
determining means is indicative of the age of the oldest
message.
24. The central controller of claim 21 wherein the age of the
messages within the memory is the average age of the messages
within the memory means, and the age signal generated by the
determining means is indicative of the average message age.
25. A central controller for receiving, handling, and transmitting
messages comprising:
receiving means for receiving a message, the message being intended
for reception by a selective call receiver, the selective call
receiver being capable of receiving a message on a predetermined
protocol;
selecting means responsive to the message for selecting a message
protocol from a plurality of message protocols, wherein the
selected message protocol corresponds to the reception protocol of
the selective call receiver;
memory means coupled to the receiving means responsive to the
selected message protocol and having a plurality of buffers,
wherein each buffer stores a plurality of messages of a like
message protocol, wherein the memory means stores the message in a
buffer corresponding to the selected message protocol and messages
stored within the buffer have a size and the messages within the
plurality of buffers have a total size;
measuring means coupled to the receiving means determining the size
of the message within the buffer and for generating a buffer size
signal in response thereof and for determining the total size of
the messages within the plurality of buffers and for generating a
total size in response thereof;
controlling means responsive to the total size signal for
generating a maximum buffer size signal as a function of the total
size signal;
analyzing means responsive to the buffer size signal and the
maximum buffer size signal for producing the buffer transmit signal
in response to the buffer size signal being substantially equal to
the maximum buffer size signal; and
transmitting means coupled to the memory means and responsive to
the buffer transmit signal for transmitting the messages within the
buffer in response to the buffer transmit signal,
thereby varying the size of the transmission of the messages stored
within the buffer as a function of the total size of the messages
within the memory means.
26. The central controller of claim 25 further comprising:
time keeping means for generating a time signal indicative of the
time of day; and wherein
the controlling means being additionally responsive to the time
signal generates the maximum buffer size signal as a function of
the total size signal and the time signal,
thereby varying the size of the transmission of the messages
accumulated within the buffer as a function of the total size of
the messages within the memory means and the time of day.
27. The central controller of claim 25 further wherein:
the messages within the plurality of batches exclusive of the batch
have an intermediate size;
the measuring means additionally determines the intermediate size
and generates an intermediate size signal;
the controlling means additionally responsive to the intermediate's
size signal generates a threshold signal in response thereof;
and
the messages stored within the buffer are transmitted in a batch
protocol wherein the messages occupy a plurality of batches and
each batch as a predetermined number of slots, a slot having either
address for message information, and a message having an address
portion and a data portion and the message being transmitted within
contiguous slots, wherein the address portion of the message may
only occur within a predetermined slot within each batch, thereby
providing for the possibility of leaving several slots within the
plurality of batches vacant of either address for data information,
wherein a batch is considered full when the number of vacant slots
within the batch is less than a threshold signal and the measuring
means determines the size of the plurality of messages as a
function of the number of full batches.
28. A central controller for receiving, handling, and transmitting
messages comprising:
receiving means for receiving a message, the message being intended
for reception by a selective call receiver, the selective call
receiving being capable of receiving the message on a predetermined
protocol;
selecting means responsive to the message for selecting a message
protocol from a plurality of message protocols for the message,
wherein the selected message protocol corresponds to the reception
protocol of the selective call receiver;
memory means coupled to the receiving means, responsive to the
selected message protocol and having a plurality of buffers,
wherein each buffer stores a plurality of messages of like message
protocol, wherein the memory means stores the message in a buffer
corresponding to the selected message protocol and message stored
within the buffer have an age indicative of the time elapsed while
the messages are within the buffer and further wherein the message
within the plurality of buffers have a total size;
determining means coupled to the memory means for determining the
age of the messages within the buffer and for generating a buffer
age signal in response thereof;
measuring means coupled to the memory means for determining the
total size of the messages within the memory means and for
generating a total size signal in response thereof;
controlling means responsive to the total size signal for
generating a maximum buffer age signal as a function of the total
size signal;
analyzing means responsive to the buffer age signal and the maximum
buffer age signal for producing the buffer transmit signal in
response to the buffer age signal being substantially equal to the
maximum buffer age signal; and
transmitting means coupled to the memory means and responsive to
the buffer transmit signal for transmitting the messages within the
buffer in response to the buffer transmit signal,
thereby varying the maximum age of messages are stored within the
buffer prior to transmission as a function of the total size of the
messages within the memory means.
29. The central controller of claim 28 further wherein:
the messages within the buffer have a size;
the measuring means additionally determines the size of the
messages within the buffer and generates a buffer size signal in
response thereof;
the controlling means additionally generates a maximum buffer size
signal; and
the analyzing means being addition responsive to the buffer size
signal and the maximum buffers size signal and generates the buffer
transmit signal in response to the buffer size signal being
substantially equal to the maximum buffer size signal,
thereby transmitting the messages within the buffer when the
maximum buffer size is substantially realized, for when the maximum
time has elapsed, whichever occurs first, and varying the maximum
time and maximum size as a function of the total size of the
message within the memory means.
30. The central controller of claim 29 wherein the controlling
means is responsive to the total size signal and the maximum buffer
size signal is generated in response to the total size signal.
31. The central controller of claim 29 wherein the maximum buffer
size signal is determined.
32. The central controller of claim 28 wherein the maximum age
signal is the product of the total size and the optimization
value.
33. The central controller of claim 32 wherein the optimization
parameter is predetermined.
34. The central controller of claim 32 further comprising:
time keeping means for generating a time signal indicative of the
time of day; and wherein
the controlling means being additionally responsive to the time
signal generates the optimization parameter as a function of the
time of day.
35. The central controller of claim 32 further comprising a means
for manually varying the optimization parameter.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a central controller for
receiving, handling and transmitting messages to a plurality of
selective call receivers.
Currently, manufactured central controllers, henceforth referred to
as paging terminals, transmit messages on a number of paging
transmission protocols. These protocols include the Golay, POCSAG,
5/6 tone, and the two-tone signalling protocols, as well as several
others. The operation of these protocols are well known to those
familiar with the art. Paging terminals generally receive messages
and determine the proper protocol for transmission of each message
and then transmits the messages to the selective call receivers.
Selective cal receivers include paging devices and henceforth are
referred to as pagers.
A number of methods are used in order to receive, handle and
transmit the messages to the pagers by the paging terminal. A first
method for handling the transmission of the messages is to transmit
the messages in the order they are received. Because of the
synchronization phenomenon associated with some of the signalling
systems, substantial delays are required between the transmission
of some protocols. The delays between the transmission of these
protocols tends to reduce the overall throughput of the paging
terminal, thereby reducing the amount of messages information that
can be transmitted on a channel, thus reducing the channel
loading.
Other paging terminals accumulate messages into their respective
protocols prior to transmission, and then transmit the messages of
each protocol. In accumulating messages in this manner, a protocol
can be transmitted without interruptions between the messages,
thereby reducing the delay between the transmission of messages.
Additionally, some protocols, such as Golay and POCSAG, require a
preamble be transmitted prior to message transmission. By
accumulating messages within their respective protocols, the
transmission of preamble signals can be substantially reduced.
Paging terminals operating in this manner may use a sequential
order for transmitting message protocols. For example, first a
Golay protocol will be transmitted followed by a POCSAG protocol
and followed by a 5/6 tone protocol and then followed by a two-tone
sequential protocol, wherein the terminal then returning back to
the first Golay protocol to transmit messages accumulated during
the transmission of the other protocols.
An improvement upon this technique has been to accumulate messages
within a protocol until a predetermined message size within the
protocol is obtained. When the size is obtained, the messages
protocol is transmitted. This technique has a disadvantage in that
messages may be held for substantially long time waiting for the
message protocol to reach a certain size prior to transmission.
This sort of message delay is undesirable in the operation of a
paging terminal. Consequently, some terminals transmit message
protocols even if they have not reached a predetermined size if the
message is within the protocol are of a certain age. However,
transmission of a protocol before an optimal size is reached
decreases the paging terminal's throughput. In order to improve the
throughput of the paging terminal, it would be advantageous to
provide a means for adjusting the maximum age of a protocol prior
to transmission, the maximum age adjustment being based upon the
channel loading characteristics.
Additionally, paging terminals receive messages of a certain
maximum size, wherein the message is received, handled and
transmitted by the paging terminal when it is less than or equal to
the maximum size. In order to improve the throughput of the paging
terminal, it would be advantageous to provide a means for adjusting
the maximum size of the message received by the paging terminal
based upon the channel loading characteristics.
Furthermore, paging terminals hold all messages of a protocol to a
constant maximum size. It is desirable for some pager users to
receive messages larger than the constant maximum size. For this
kind of message service, some pager users would be willing to pay a
premium. Alternately, some pager users wish to economize on the
message service payment and would accept messages smaller than the
constant maximum size. Thus, it would be desirable to establish a
means for individually determining maximum message size of a
message according to each pager user. It would also be desirable to
adjust this individual maximum message size based upon the channel
loading characteristics.
Additionally, the tariff structure of paging messaging is typically
a fixed monthly price independent of the time of day in which a
message is transmitted. Thus there is no motivation for users of a
paging service to defer messaging to hours of the day where the
system were not so heavily loaded. Thus it would be advantageous to
provide a billing means which varies the tariff charge for
messaging on the basis of the time of the day, wherein the time of
day corresponds to system loading.
Channel loading characteristics are predictable based upon the time
of day. FIG. 1 shows a prior art illustration of the system loading
or channel loading of a typical paging transmission channel. Given
these characteristics, it would be desirable to provide a means for
adjusting the maximum size of an incoming message by the time of
day. Also, it would be desirable to provide adjustment of the
maximum size of the messages accumulated within a protocol buffer
by the time of day in order to optimize the system throughput.
Furthermore, it is desirable to optimize the maximum age of
messages accumulated within the protocol buffer by the time of day
in order to balance the throughput with the message delay.
An indication of the channel loading also can be found by
determining the total message held within the paging terminal. It
would also be desirable to increase the throughput of the paging
terminal by adjusting the input message size, the maximum size and
the maximum age of messages accumulated within a protocol, based
upon the total messages held within the paging terminal. Finally,
it would be desirable to increase the throughput by adjusting these
same parameters as a combination of the total messages within the
paging terminal and the time of day.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a
means for adjusting the size of an incoming message by the time of
day.
It is another object of this invention to provide means for
adjusting the size of an incoming message in response to the total
size of a message held within a paging terminal.
It is another object of the present invention to adjust the maximum
size of the message transmission of a protocol based upon the time
of day.
It is another object of this invention to adjust the maximum size
of a protocol transmission based upon the total size of the message
held within the paging terminal.
It is another object of this invention to adjust the maximum age of
the message held within a protocol prior to transmission based upon
the time of day.
It is yet another object of this invention to adjust the maximum
age of the message held within a protocol prior to transmission
based upon the total size of the messages held within a paging
terminal.
It is a further object of the present invention to provide a time
of day clock for controlling and modifying operational
characteristics within a paging terminal. The operational
characteristics may include modifying the maximum size of an
incoming message, the tariff charged for messaging, or the maximum
size of a protocol transmission.
These and other objects of this invention will become clear as the
description proceeds.
BRIEF DESCRIPTION OF HE DRAWINGS
FIG. 1 shows a prior art graphical representation of the system
leading for a typical paging channel.
FIG. 2 shows a block diagram of the central controller of the
present invention.
FIG. 3 shows tasks within the multi-tasking environment of the
paging terminal necessary to perform the functions of the present
invention.
FIG. 4 shows a flow chart of the message receiving operation.
FIG. 5 shows a technique for determining the maximum message
size.
FIG. 6 shows an alternate technique for determining the maximum
message size.
FIG. 7 shows another alternate technique for determining the
maximum message size.
FIG. 8 shows a graphical representation of the relationship between
the time of day and the maximum incoming message size.
FIG. 9 shows a graphical representation of the relationship between
the maximum message size and the total size of messages held within
the message memory means.
FIG. 10 shows a flow chart for storing a message in a corresponding
protocol buffer.
FIG. 11 shows a flow chart detailing the analysis of protocols for
size and age and enabling transmission in response thereof.
FIG. 12 shows the operation of the format controller.
FIG. 13 shows a technique for determining the size of a buffer.
FIG. 14 shows an alternate technique for determining the maximum
size of a buffer.
FIG. 15 shows another alternate technique for determining the
maximum size of a buffer.
FIG. 16 shows a graphical representation of the relationship
between the maximum buffer size and the time of day.
FIG. 17 shows a graphical representation of the relationship
between the maximum buffer size and the total size of the messages
held within the message memory means.
FIG. 18 shows a technique for determining the maximum age of a
buffer.
FIG. 19 shows an alternate technique for determining the maximum
buffer age.
FIG. 20 shows another alternate technique for determining the
maximum buffer age.
FIG. 21 shows a graphical representation of the relationship
between the maximum buffer age and the time of day.
FIG. 22 shows a graphical representation of the relationship
between the optimization value and the time of day.
FIG. 23 shows a typical protocol transmission of the POCSAG
protocol as well as ways for determining the size of the POCSAG
protocol transmission.
FIG. 24 shows a flow chart indicating a technique for determining
the size of the POCSAG protocol shown in FIG. 23.
FIG. 25 shows a technique for determining the threshold value of a
POCSAG batch.
FIG. 26 shows an alternate technique for determining the threshold,
value of a POCSAG batch.
FIG. 27 shows a second alternate technique for determining the
threshold value of a POCSAG batch.
FIG. 28 shows a graphical representation relating the threshold
value to the time of day.
FIG. 29 shows a graphical representation equating the threshold
value to the total size of the messages within the message memory
means.
DESCRIPTION OF A PREFERRED EMBODIMENT
According to the principals of the present invention, the loading
for paging systems is dependent upon the time of day because the
primary users for pager systems are active during conventional
business hours. Other users require their pagers to be active
twenty-four hours a day. These users account for most of the system
loading during "off hours". The system loading for a typical paging
channel is graphically shown in FIG. 1. Early morning hours 12:00
A.M.-6:00 A.M. are usually lightly loaded times. As the day
progresses, loading gradually increases until peak loading hours
occur between 10:00 A.M.-4:00 P.M. System loading then gradually
decreases and the cycle repeats. System loading is detailed in the
U.S. Pat. No. 4,701,943 entitled "Paging System Using LPC Speech
Including with an Adaptive Bit Rate" issued to Walter Davis et al.
which is hereby incorporated by reference.
FIG. 2 shows a block diagram of the central controller of the
present invention. The central controller 40 receives messages for
the pagers typically from senders using telephones 42, the messages
are received by message receiving means 44, and the size of the
message may be limited by message limiting means 46. Protocol
determining means 48 stores the message in a message memory means
50 in a corresponding protocol buffer 52, 54 or 56. Additionally,
the protocol determining means starts a timer in timing means 60 in
the appropriate protocol timer 62, 64 or 66 if the corresponding
protocol buffer is empty when the message is stored. The timer's
use includes determining the age of messages within the protocol
buffers. When a protocol buffer is ready to transmit, a
corresponding protocol formatter 68, 70 or 72 formats the contents
of the buffer into a transmittable protocol and submits the
protocol to transmitter 74, thereafter the messages within the
protocol are transmitted to selective call receivers.
A protocol may be a Golay, POCSAG, 5/6 tone, or twotone message. In
the present invention, POCSAG messages would be stored in a
protocol buffer corresponding to POCSAG. Golay messages with a
common preamble would be stored in a common protocol buffer.
Five/six tone messages and two-tone messages may be stored in
another common buffer. It should be noted that although only three
protocol buffers are shown in FIG. 2, the number of protocol
buffers, as well as the number of protocol timers and protocol
formatters, may be extended to include all the necessary protocols
handled by the paging terminal.
The message size the message limiting means 46 limits the incoming
message to is determined by analyzer and control means 76. The
message receiving means identifies message characteristics for the
analyzer and control means 76. The message characteristics allow
the control means 76 to determine the message protocol and the
individual maximum message size associated with the pager. The
analyzer and control means then, in response to the control memory
means 78, the time of day clock 80 and the parameter input device
82, determines the appropriate size for limiting the message and
causes the message limiting means 46 to correspondingly limit the
size of the incoming message.
The analyzer and control means 76 additionally determines the size
of the messages within each buffer in memory means 50 as well as
the age of the messages within the protocol buffers as indicated by
the corresponding protocol timer in timing means 60 and then
generates transmit signals. The determination for the size and/or
age of a protocol buffer are determinate in response to input from
control memory means 78, time of day clock 80 and parameter input
device 82. The transmit signals are then delivered to the
corresponding protocol formatter 6872 and the messages ultimately
transmitted through transmitter 74.
The operation of paging terminal 40 may be typically controlled by
a computer base paging terminal such as the Modax paging terminal
manufactured by Motorola, Inc. The general operation of
computer-based paging terminals are well known to those familiar
with the art and generally operate with multi-tasking software.
FIG. 3 shows tasks within the multi-tasking environment of the
paging terminal necessary to perform the functions of the present
invention. Step 90 of task 1 shows the process of receiving a
message with size limiting. Step 92 of task 1 shows storing the
message within an appropriate protocol. Step 96 of analyzing task 2
shows the process of analyzing protocol for size and age and
enabling transmission of the protocol. Step 98 of task 3 shows the
step of examining the protocols and transmitting the protocol if
enabled and restart the protocol timer. In the multi-tasking
environment, tasks 1, 2, and 3, as well as additional tasks
necessary to perform the proper operation of the paging terminal,
are effectively performed concurrently. Thus, the programs within
each task effectively operate simultaneously. A detailed
description of tasks 1 through 3 follows herein.
There are several techniques for determining message size. A first
technique is to monitor the time that a telephone 42 is connected
to message receiving means. This technique results in a message
size measured in seconds. A second technique is to determine the
amount of air time a message consumes while being transmitted. With
this technique, message size is also measured in seconds. A third
technique is to measure the amount of message memory occupied by
the message while stored in the message memory means 50. Since
voice messages are typically digitized and stored in binary memory
prior to transmission, and digital messages are also stored in
binary memory, it is possible to measure the size of a message by
determining the number of binary elements the message occupies
within the message memory means. Each of these techniques works
well, and each protocol within the terminal may have a different
technique for measuring message size.
FIG. 4 shows a flow chart of the message receiving operation, step
90, of task 1. The computer program within the paging terminal in
step 100 checks if an incoming message is being received from a
sending unit 42. If no message is received, the program returns to
step 100 until a message is received. In the event a message is
received, the program proceeds to step 101 to determine the maximum
size of the message. The maximum size may be common to all messages
received by the paging terminal. Alternatively, the maximum size
may depend upon message characteristics such as the protocol of the
message or the individual user preference for maximum message
length. It can be appreciated that a number of individual users
desiring the same maximum message length can be formed into a user
group. Thus, a message characteristic can include a user group and
the maximum message length can be determined accordingly. The
program then proceeds to step 102 to indicate the maximum size of
the incoming message. In the event of a voice message, the
indication of step 102 would take the form of a message from the
paging terminal to the caller indicating that a voice message of up
to say seven seconds, for example, will be accepted. As will be
detailed later, the maximum size of the incoming message may vary
either by the time of day or by the size of messages held within
the paging terminal, and the maximum size indication corresponds to
the current maximum message size accepted by the paging terminal.
The program then proceeds to step 104 to receive the message. The
program then proceeds to step 106 to check that the maximum size is
not exceeded. If the maximum size is not exceeded, the program
proceeds to step 108 to check if the message is ended. In a voice
message, the message may have been ended by the caller hanging up
the telephone. If the message is not ended, the program returns to
step 104 to continue receiving the message. If in step 108 the
message is ended, the program proceeds to step 110 to store the
message in a corresponding protocol buffer. If, however, in step
106 the maximum size is exceeded, the program proceeds to step 112
to limit the message size. Limiting the message size may include
truncating the message when the maximum sizes is reached. In the
case of a voice message, limiting the message size may also include
removing the silence spaces from the voice message in order to keep
the voice message limited to the maximum size.
FIG. 5 shows a technique for determining the maximum message size
of step 101 of FIG. 4. First, in step 120, the time of day is
determined. The time of day is determined by examining the time of
day clock 80. Second, in step 122, the maximum message size looked
up in the control memory means 78 corresponding to the time of day
and the message characteristic.
FIG. 6 shows an alternate technique for determining the maximum
message size of step 101. In step 126, analyzer and control means
76 examines the size of the messages within the message memory
means 50 including the protocol buffers, 52, 54 and 56, and
determines the total size of the messages therein. Note that it is
not necessary that the determination be made based upon all buffers
within memory means 50, for example, a representative number of
buffers or a particular set of buffers may be chosen for the total
size determination. Next, in step 128, the program looks up the
maximum message size held within the control memory means 78
corresponding to the total message size determined in step 126 and
the message characteristic.
FIG. 7 shows another alternate technique for determining the
maximum message size of step 101. In step 130, the time of day is
determined from time of day clock 80. The program proceeds to step
132 to determine the total size of messages within the message
memory means as described in step 126 of FIG. 6. The program then
proceeds to step 134 to look up a time message size in the control
memory means corresponding the time of day and the message
characteristic. The program then proceeds to step 136 to determine
the maximum message size as the time message size of step 134 minus
the total message size of step 132 times a number .01.
FIG. 8 shows a graphical representation of the table of numbers
held within control memory means 78. The table of numbers indicate
the relationship between the time of day and the maximum incoming
message size. Memory means 78 may have a plurality of tables, each
table having a different relationship between time of day and the
maximum message size wherein each table corresponds to a particular
message characteristic. It can be seen from FIG. 8 that during the
early morning hours 12:00 A.M. to 6:00 A.M. when the channel is
usually lightly loaded, the maximum message size is longer,
typically up to 18 seconds. As the day progresses, the incoming
message size gradually decreases until during peak loading between
the hours of 10:00 A.M. to 4:00 P.M. The maximum message size is
limited to about 7 seconds. Then the maximum message size is
allowed to increase to the 18 second message size and the cycle
repeats. The graphical representation of FIG. 8 also represent the
maximum message size determined in step 122 as well as the time
message size determined in step 134.
When the system is lightly loaded, the message sizes are typically
allowed to be long, up to 18 seconds and then as the system loading
is expected to increase, the maximum incoming message size is
decreased, thus allowing for long messages when the channel is
lightly loaded and shortening the message as the channel loading
increases.
It should be noted that although FIG. 8 shows a maximum message
size of about 7 seconds between the hours of 10:00 AM and 6:00 PM,
FIG. 8 could, for example, be redrawn to allow zero seconds between
these hours. This would effectively eliminate paging service during
the time between 10:00 AM and 6:00 PM to the pager user having such
a message characteristic. A pager user with such a message
characteristic would be able to economize on paging service by only
receiving pages at times when the paging terminal is not heavily
loaded. Between the hours of 10:00 AM and 6:00 PM, no messages of
this message characteristic would be received by the paging
terminal. If a message were received between the hours of 10:00 AM
and 6:00 PM, step 102 of FIG. 4 could inform the caller that
messages were not being received at this time and that messages
would be received after 6 PM.
FIG. 9 shows a graphical representation of the table within the
control memory means 78 relating the maximum message size to the
total size of messages held within the message memory means 50 and
the message characteristic. Note that the total message size is
indicative of the system loading. As can be seen from FIG. 9, the
maximum incoming message size is limited to 18 seconds when the
total message size is less then 75 seconds. As system loading
increases, the total message size decreases. As the total message
size increases from 75 to 125 seconds, the maximum income message
size decreases from 18 seconds to 7 seconds. As the total message
size increases beyond 125 seconds, the maximum incoming message is
limited to 7 seconds. It can be appreciated that a pager user
wishing to economize on paging service could subscribe a message
characteristic that had a message time of zero seconds at a
predetermined total message size. In such a case, the messages of
this message characteristic would not be received by the paging
terminal when the total message size reached a predetermined size.
The maximum incoming message size of FIG. 9 is the value determined
in step 128 of FIG. 6.
FIG. 10 shows the flow chart for storing a message in a
corresponding protocol buffer. This corresponds to step 92 of task
1 of FIG. 3. First, the program receives the messages and
determines the protocol type in step 150. The program proceeds to
step 152 to check if the corresponding protocol buffer is empty. If
in step 152 buffer is empty, the program starts the corresponding
protocol buffer timer in timing means 60 in step 154. The program
then proceeds to step 156 to store the message in the corresponding
protocol buffer. If in step 152 the corresponding protocol buffer
is not empty the program then proceeds to step 156.
FIG. 11 shows a flow chart detailing the analysis of protocols for
size and age enabling transmission in response thereof. This
corresponds to the operation, step 96 of task 2, of the
multi-tasking operation of the paging terminal. In FIG. 11, the
values of S1 through Sn and Al through An are constant at any point
in time. However, the multi-tasking paging terminal constantly
adjusts these values. FIGS. 13-22 show flow charts detailing the
adjustment of these values. In step 160, protocol 1 buffer size is
determined and the size is checked to be greater than the value S1.
If the value is not greater than S1, the program proceeds to step
162 to check if the protocol 1 timer has a value greater than Al.
If the protocol has a value greater than timer Al in step 162, or
if the protocol has a size greater than S1 in step 160, the program
proceeds to step 164 to indicate that the protocol 1 buffer is
ready to transmit.
The program then proceeds to step 166 from either step 162 or step
164. Similar to step 160, in step 166, protocol 2 buffer size is
determined and if the buffer size is less than a value S2, the
program proceeds to step 168 to check if protocol 2 timer has a
value greater than a A2. If the protocol 2 timer has a value
greater than A2 or if a protocol to buffer size has a size greater
then S2 in step 166, the program proceeds to step 170 to indicate
that the protocol 2 buffer is ready to transmit.
The program proceeds from either step 168 or step 170 to step 172
to check if protocol in buffer is greater than a value Sn. If not,
the program proceeds to step 174 to check if the protocol in timer
has a value greater than An. If in step 174 the protocol timer has
a value greater than An or if in step 172 the buffer size has a
value greater than Sn, the program proceeds to 176 to indicate that
protocol N is ready to transmit. It can be appreciated that
although only 3 protocol buffers are shown here protocol 1,
protocol 2 and protocol n, FIG. 11 can be extended to include as
many protocol and protocol buffers as required to operate the
paging terminal
FIG. 12 shows the operation of the format controller of step 98 of
task 3 of the multi-tasking environment of the paging terminal.
First, in step 180, the protocol 1 is checked to be ready to
transmit. The determination to transmit was made in step 164 of
FIG. 11. If the protocol 1 is ready to transmit, the program
proceeds to step 182 to transmit any necessary preamble for
protocol 1. Necessary preambles for protocol such as the POCSAG and
Golay protocols are well known to those familiar with the art. The
program then proceeds to step 184 to get a message from the
protocol 1 buffer and format and transmit the message. The program
then proceeds to step 186 to check if the protocol 1 buffer is
empty. If in step 186 the protocol 1 buffer is not empty, the
program returns to step 184 to get the next message from the
protocol buffer. After all of the messages from the protocol buffer
are transmitted, the program proceeds to step 188 to reset and stop
the protocol 1 timer within the timing means 60. Note that the
protocol 1 timer will be restarted by execution of step 154 when a
message is stored in protocol. After completion of step 188, the
program proceeds to step 190. Also in step 180, if the protocol 1
buffer was not ready to transmit, the program proceeds to step 190.
In step 190, protocol 2 buffer is checked to be ready to transmit.
The indication that this buffer is ready to transmit was made in
step 170 of FIG. 11. If protocol 2 buffer is ready to transmit, the
program proceeds to step 192 to transmit any necessary preamble for
protocol 2. The program then proceeds to step 194 to get a message
from the protocol 2 buffer 54 of message memory means 50 and format
and transmit the message. The program then proceeds to step 196 to
check if the protocol 2 buffer is empty. If in step 196 the
protocol 2 buffer is not empty, the program returns to step 194 to
get the next message. The program executes steps 194 and 196 until
the protocol 2 buffer is empty, at which time the program proceeds
to step 198 to reset and stop the protocol 2 timer. The program
then proceeds to step 200. Also if in step 190 the protocol 2
buffer is not ready to transmit, the program proceeds to step 200.
In step 200, protocol N. is checked to be ready to transmit, the
protocol N buffer being indicated ready to transmit by step 176 of
FIG. 11. If protocol N is ready to transmit, the program proceeds
to step 202 to transmit any necessary preamble for protocol N. The
program then proceeds to step 204 to get a message from the
protocol N buffer and format and transmit it in a manner similar to
steps 184 and 194. The program then proceeds to step 206 to check
if protocol N buffer is empty. If protocol N buffer is not empty,
the program executes steps 204 to 206 until the buffer is empty.
When the protocol N buffer is empty, the program proceeds to step
208 to reset and stop the protocol N timer. After step 208, or if
in step 200 the protocol N buffer is not ready to transmit, the
program returns to step 180 to examine the protocol 1 buffer for
being ready to transmit.
FIG. 12 shows how the program scans each of the protocol buffers
within the paging terminal. When a buffer is ready to transmit, the
messages within the buffer are transmitted.
FIG. 13 shows a technique for determining the value Sn used in FIG.
11 for determining the maximum size of a buffer before it is ready
to transmit. The values for Sn in this figure, as well as in FIGS.
14 and 15, may be common to all protocols, or each protocol may
have a unique value of Sn, thereby allowing each protocol to have a
unique maximum buffer size. In step 220, the time of day is
determined from time of day clock 80. Then in step 222, the value
for Sn corresponding to the protocol is looked up in control memory
means 78 for the time of day.
FIG. 14 shows an alternate technique for determining the maximum
buffer size Sn. In step 224, as in step 126, the total size of the
messages within message memory means 50 is determined. In step 226,
the value for Sn corresponding to the buffer is looked up in
control memory means 78 corresponding to the total message size
determined in step 224.
FIG. 15 shows another alternate technique for determining the
maximum buffer size for Sn. In step 228, the time of day is
determined from time of day clock 80. As in step 126, the total
size of the messages within message memory means 50 is determined
in step 230. In step 232, a value for Sm is looked up in control
memory means for the time of day. Then in step 234, a value for Sn
is calculated as the Sm value of step 232 plus the total message
size of step 230 times a number of 0.01.
FIG. 16 shows a graphical representation of a table within the
control memory means 78 relating the maximum buffer size Sn to the
time of day. During the early morning hours 12:00 A.M. through 6:00
A.M. when the system is lightly loaded, the maximum buffer size is
about 10 seconds. As the day progresses and the loading gradually
increases until peak loading between 10:00 A.M. and 4:00 P.M., the
maximum buffer size is increased to 40 seconds. Then as channel
loading gradually decreases to 8:00 P.M., the maximum buffer size
Sn is decreases to about 10 seconds. Note that this technique
requires that a larger size protocol be held prior to transmission
during the heavily loaded times of the system operation.
Transmitting a large number of messages within a protocol increases
the overall throughput as described earlier. However, during the
lightly loaded hours, the size of the protocol prior to
transmission is reduced enabling more rapid transmission of
messages help within the paging terminal.
FIG. 17 shows a graphical representation of a table within control
memory means 78 relating the maximum buffer size Sn to the total
size of the messages held within the message memory means. The
values of FIG. 16 are used in steps 222 for Sn as well as step 232
for Sm. The value for Sn of FIG. 17 is used in step 226 of FIG. 14.
Note in FIG. 17 that when the total size of the messages within the
message memory means is less than 75 seconds, the maximum buffer
size before transmission is about 10 seconds. However, as the total
size of messages within message memory means increase from 75
seconds to 125 seconds, the maximum buffer size before transmission
of the buffer is increased to about 38 seconds. Then, beyond the
125 seconds total message size within the message memory means, the
maximum buffer size is held to 38 seconds. Note that as the total
size of the message in the memory means increases beyond 75
seconds, this indicates that the channel is becoming more heavily
loaded. Thus, as the channel becomes more heavily loaded, the size
of the messages within a buffer increases before the buffer is
transmitted. This graph shows another technique for increasing the
size of the messages held within a buffer prior to transmission as
a function of the system loading.
FIG. 18 shows a technique for determining the maximum buffer age An
and represents a value for Al in step 162, A2 step 168, and through
as many protocols as required through An in step 174. For FIGS. 18,
19, and 20, the value for An may be the same for all protocols or
may be independent from one protocol to the next. In FIG. 18, step
240, the time of day is determined from time of day clock 80. Then
in step 242, a value for An is looked up in control memory means 78
corresponding to the time of day. This value for An may be used in
steps 162, 168, and 174.
FIG. 19 shows an alternate technique for determining the maximum
buffer An. In step 244, as in step 126, the total size of the
messaged within message memory means 50 is determined. Then in step
246, a value Am is determined to be a product of the total size
determined in step 244 times an optimization value. Then in step
248, the value Am is checked to be less than a minimum value for
An. If in step 248 Am is not less than a minimum value, then in
step 250, An is made equal to a Am. However, if in step 248 Am is
less than An, the minimum value for An is chosen in step 252. The
value chosen in 250 or step 252 is used for An in steps 162, 168,
and 174. The optimization value of step 246 may be either a
predetermined optimization value or entered from the parameter
input device 82. This technique allows a system operator to have
control over the maximum age of messages help within the paging
terminal prior to transmission.
FIG. 20 shows another alternate technique for determining the
maximum buffer age An. In step 256, the time of day is determined
from time of day clock 80. Then in step 258, as in step 126, the
total size of messages was in message memory means 50 is
determined. In step 260, minimum values for An and an optimization
value are looked up in the control memory means 78 based upon the
time of day. This step allows An and the optimization value to be
be varied by the time of day and the expected system loadings at
these times of day. Then in step 262, a value for Am is chosen to
be the total size determined in step 258 multiplied by the
optimization value determined in step 260. Then in step 264, the
value of An of step 262 is determined to be less than a minimum
value for An determined in step 260. If it is not, the value for An
is chosen to be equal to Am in step 266, otherwise in step 268, the
value for An is chosen to be equal to a minimum An. The technique
shown in FIG. 20 provides for both a minimum age of a buffer prior
to transmission when the system is not busy, and as the paging
channel grows busier, the minimum age becomes a product of the
total size of the messages within the paging terminal to be varied
as the time of day.
FIG. 21 shows a graphical representation of a table within control
memory means 78 equating the maximum buffer age An with the time of
day. Note that during the times between 12:00 A.M. and 6:00 A.M.
when the system is lightly loaded, the maximum buffer age is low,
about 20 seconds. As the day progresses and loading gradually
increases to a peak loading between 10:00 A.M. and 4:00 P.M., the
maximum buffer age is increased to about 115 seconds. Then as
system loading gradually decreases, the maximum buffer age prior to
transmission is decreased to about 20 seconds. This technique
allows a buffer age to build up a optimal size prior to
transmission during a heavily loaded time. However, when the
channel is not heavily loaded, the buffer age prior to transmission
is decreased, thus providing for quicker message handling during a
lightly loaded time. The buffer age corresponds to the values of An
in step 242 and the minimum An of step 260.
FIG. 22 shows a graphical representation of a table within the
control memory means 78 relating the optimization value used in
steps 246 and 262 versus the time of day. Note that during the
lightly loaded hours between 12:00 A.M. and 6:00 A.M., the
optimization value is low, approximately 0.2, and then as the day
progresses, the optimization value gradually increases until peak
loading hours between 10:00 A.M. and 4:00 P.M. where the
optimization value is approximately 0.45. Then as system loading
decreases, the optimization value returns to approximately 0.2.
This technique allows the maximum age being a product of the total
size of messages within a memory means and the optimization value
to be varied as the system loading varies. This technique also
allows the age of the messages within the buffer to increase as
system loading increases giving the buffer more time to reach an
optimal size prior to transmission.
The size of messages within a protocol buffer has been referred to
as measured in seconds. However, a number of ways exist to
represent the size of messages within a buffer. It is desirable to
vary the criterion for determining the size of a buffer with
respect to system loading. FIG. 23 shows a typical protocol
transmission of the POCSAG protocol. The operation of the POCSAG
system is well known to those familiar with the art and will not be
detailed herein. The POCSAG transmission shown in FIG. 23 consists
of a POCSAG preamble signal and two POCSAG batches. Each POCSAG
batch is preceded with a sync code indicated by the label SC in
slots on line 280. Between each of the sync codes are 16 slots
containing either address information, data information or idle
code information. A message consists of an address optionally
followed by data. An address is indicated by the letter A in a
slot, data is indicated by the letter D in the slot, and an idle
code which contains neither address nor data information is
represented by the letter X in the slot. The first way to measure
the size of this protocol transmission is to measure the overall
time required to transmit the preamble and the two batches. This
time is 3.2 seconds. A second way to indicate the size of this
transmission is to count the number of batches having message
information in them. Using this criterion, the protocol represented
by FIG. 23 has a size of two batches. A third technique for
determining the size of the protocol is to count the number of
messages within the protocol. In this case, line 282 details the
messages within the batches. In this example, there are six
messages total, and using this technique, the protocol would have a
total size of six messages. A fourth technique to determine the
size of the protocol transmission is to determine the amount of
information necessary to be stored within the memory means or
within the protocol buffer in order to create the transmission.
This can be determined by counting the number of address and data
slots within the protocol. In this example, there are six slots
having address information and sixteen slots having data
information resulting in a total size of 22 slots, the 22 slots
being indicative of the size of the memory used by the protocol
buffer.
FIG. 24 shows a flow chart indicating a fifth technique for
determining the size of the buffer show in FIG. 23. The flow chart
of FIG. 24 shows a way to vary the criterion for determining the
size of a POCSAG buffer with respect to system loading. First, in
step 290, the total number of slots having address or data
information within a batch is determined. Note that each batch has
a constant sixteen slots. Then in step 292, this value is checked
to be greater than a threshold value. If this is greater than a
threshold value, the batch is counted as full in step 294. However,
if not, the program proceeds to step 296 to check if all batches
have been counted. If all batches have not been counted, the
program proceeds to step 298 to check for the next batch and
execute the steps of 290 through 296 until all batches are counted.
Finally, in step 300, the size is determined to be equal to the
number of full batches determined by execution of step 294, the
size resulting from step 300 being the size of a POCSAG protocol
buffer contained within the message memory means 50.
Note that the threshold value 292 may be predetermined. In the case
of POCSAG, if the threshold value is 12 slots, FIG. 24 requires
that at least 12 slots within a batch have address or data
information in order for that batch to be considered full. For
example, using FIG. 23, the first batch contains 13 slots having
address or data information. Under this criterion, the first batch
would be considered full. However, the second batch has only 10
slots having address or data information. Under this criterion, the
second batch would not be considered full. Thus, the size of the
protocol buffer shown by FIG. 23 would be one batch.
FIG. 25 shows a technique for determining the threshold value used
in step 292. First, in step 310, the time of day is determined from
time of day clock 80. Then in step 312, a threshold value
corresponding to the time of day is looked up in control memory
means 78. This technique allows the control value to be varied by
the time of day, thereby regulating the amount of slots containing
address and data information necessary for a batch to be considered
to be full based upon the time of day.
FIG. 26 shows an alternate technique for determining the threshold
value used in step 292. First, in step 314, similar to step 126,
the total size of messages within the memory means excluding a
POCSAG buffer is determined. Second, in step 316, the threshold
value corresponding to the total size is looked up in control
memory means 78. This technique allows the number of slots
containing address or data information in order for a batch to be
considered full to be varied corresponding to the total size of the
messages within the memory means.
FIG. 27 shows a second alternate technique for determining
threshold value. First, in step 320, the time of day is determined
from time of day clock 80. Then in step 322, similar to step 126,
the total size of the messages within the memory means excluding
the POCSAG buffer is determined. Then in step 324, a time value is
looked up in the control memory means 78 corresponding to the time
of day. Next, in step 326, a threshold value is calculated to be
equal to the time value determined in step 324 plus the total
message value determined in step 322 multiplied by a constant 0.01.
This technique allows a number of slots containing address and data
information in a POCSAG batch in order for the batch to be
considered full to be varied as both a function of the time of day
and the total size of the messages held within the paging
terminal.
FIG. 28 shows a graphical representation of a table within control
memory means 78 relating the minimum number of slots with
information for a full batch versus time of day. This equates to a
threshold value looked up in step 312 and the time value looked up
in step 324. Note that during the early morning hours 12:00 A.M. to
6:00 A.M. when the system is usually lightly loaded, the number of
slots having address and data information is approximately 6. Thus,
a batch may contain a large number of empty or idle code slots in
order for the batch to be considered full. As the day progresses,
loading gradually increases until peak loading occurs between 10:00
A.M. and 4:00 P.M., wherein the number of slots increases to 12,
thereby requiring more information to be included within the packet
in order for the packet to be considered full. Then as system
loading gradually decreases, the number of slots containing address
for data information also gradually decreases to 6 slots.
FIG. 29 is a graphical representation of a table within control
memory means 78 equating the minimum number of slots with
information for a full batch versus the total size of messages
within the memory means. This equates to the value looked up in
step 316. Note that as the total size of messages within the memory
means is low or less than 75 seconds, the number of slots having
address or data information in order for a batch to be considered
full is about 6. However, as the total size of messages in the
memory means increases corresponding to an increase in system
loading, a minimum number of slots with information for a full
batch also increases to 12. After 125 seconds of messages in the
message memory means, a constant value of 12 or more slots is
required for POCSAG batch to be considered full. The graph of FIG.
29 illustrates that during a lightly loaded system, a POCSAG batch
does not have to have as much address or data information to be
considered full as during the heavily loaded system.
Note that the determination of the POCSAG protocol size based upon
the techniques shown in FIGS. 24-29 allow the determined size of a
POCSAG protocol to be varied over the time of day. Particularly
note that in FIG. 23, during the heavily channel loaded times,
FIGS. 28 of 29 have the minimum number of slots containing address
or information within a POCSAG batch to be considered full limited
to 12. Using this analysis, the size of the protocol shown in FIG.
23 would be one batch. However, during the lightly loaded times as
illustrated by FIGS. 28 or 29, the minimum number of slots within a
POCSAG batch having address or information in order for that batch
to be considered full is reduced to 6. Upon examining the protocol
of FIG. 23 using the flow chart of FIG. 24 with a threshold value
of 6 the size of the protocol of FIG. 23 is two batches. Therefore,
during the heavily loaded times, the size of the protocol of FIG.
23 is only one batch. However, during lightly loaded channel times,
the size of the protocol of FIG. 23 is two batches. This technique
allows the information density of a POCSAG type batch to be varied
versus channel loading.
In a preferred embodiment of the invention the output of the time
of day clock 80 is converted by control means 76 into a four level
signal which controls various characteristics or operations of the
paging terminal. The programming of the values of the four levels
and the times in which the levels are activated may be made by
parameter input device 82. The limitation of the clock signal to
four levels greatly simplifies the programming, design and
implementation of the paging terminal. As can be seen by the charts
of FIGS. 8, 16, 21, and 28 and discussions related thereto, that a
great number of characteristics may be varied by the time of day
and preferably by a four level signal generated as a result of the
time of day. These characteristics include varying the tariff
charged for each message received, similar to the long distance
billing structure used in the telephone industry. Other
characteristics include varying the size of an incoming message,
inhibiting reception of messages from selected message sources,
varying the size or age of messages within a protocol buffer
necessary for transmission, or a parameter used to determine to
size of messages within a protocol buffer on the basis of the time
of day. Alternate embodiments may increase or decrease the number
of levels produced in response to the time of day clock.
It can be obvious that the number of alterations to the operation
of the present invention may be made without departing from the
spirit and scope of the claimed invention. Note the graphical
representations of FIGS. 8, 9, 16, 17, 21, 22, 28, and 29 represent
one embodiment of the present invention. Other representations may
be made to account for various applications of central controllers
while still remaining within the scope of the present
invention.
* * * * *